Resist materials used for etching or plating with conventional printed circuit board manufacturing technology include widely employed photosensitive elements obtained using photosensitive resin compositions, or the same laminated onto supports and covered with protective films.
For ordinary production of printed circuit boards, first a photosensitive element is stacked (by lamination or the like) onto a circuit-forming board such as a copper board with a layer composed of a photosensitive resin composition (hereinafter referred to as “photosensitive layer”) bonded thereto, and irradiated with active light rays for photocuring (pattern exposure) of prescribed sections of the photosensitive resin composition, after which the non-photocured sections of the photosensitive resin composition are removed to form a resist pattern (development). Finally, a pattern is formed by etching or plating of the circuit-forming board on which the resist pattern is to be formed, and the photocured sections of the photosensitive resin composition are then released and removed from the board.
In the field of flat panel displays (FPD), it is known that plasma display panels (PDP) are capable of faster display than liquid crystal panels and can be upsized more easily. Because of these advantages, PDPs have become widely used as OA devices and public display devices. Further advancement of PDPs for the field of high definition television in the future is also foreseen.
With such diversifying uses, a great deal of interest is being drawn toward color PDPs comprising numerous fine display cells. In a PDP, the front glass panel and the back glass panel are situated parallel and opposite to each other, and a barrier is provided at an equal spacing between them. The PDP has a construction whereby discharge occurs in the space surrounding the front glass panel, back glass panel and barrier. Electrodes, a dielectric material layer and a fluorescent material are included in the space for display. The fluorescent material is induced to emit light by ultraviolet rays emitted from the filler gas by the discharge, and this light is visible to the viewer. In order to limit the extent of discharge to a specific region and ensure a uniform discharge space while producing display within the specified cell, the barrier has a shape with a width of 20-80 μm and a height of 60-200 μm.
The method usually employed for forming the barrier is a sand blast method, screen printing method, photosensitive paste method, photo-casting method or mold transfer method. Methods of formation by wet etching processes have also been proposed in recent years.
For production of a barrier, for example, a barrier material layer is formed on a back glass panel on which an electrode has been formed and a photosensitive element is stacked (by lamination or the like) onto the photosensitive layer comprising the photosensitive element bonded to the barrier material layer, after which it is irradiated with active light rays for photocuring (pattern exposure) of prescribed sections of the photosensitive resin composition and the non-photocured sections of the photosensitive resin composition are then removed (developed) to form a resist pattern. Finally, the resist pattern is used as a mask for etching of the barrier material layer to form a barrier pattern and the resist pattern is released and removed.
Mercury lamps have conventionally been used as light sources for pattern exposure of photosensitive layers. However, mercury lamp light includes ultraviolet rays that are harmful to the human body, and therefore worker safety has been an issue. Methods of exposure also exist that use visible light lasers as light sources, but such methods require resists that are sensitive to visible light and which must therefore be handled in darkrooms or under red lamps.
In light of such problems, it has been proposed to use active light rays emitted from mercury lamp light sources from which 99.5% of the light with a wavelength of 365 nm and shorter has been cut using a filter. In recent years it has also been proposed to employ gallium nitride-based blue laser light sources that have long usable life and high output, and oscillate light with a wavelength of 405 nm.
Other proposals in recent years involving new exposure techniques include direct writing methods such as DLP (Digital Light Processing) (for example, see Non-patent document 1). The light sources employed in these exposure methods are also mercury lamp light sources as active light sources with 99.5% of the light with a wavelength of 365 nm cut out using a filter, or blue laser light sources.    [Non-patent document 1] Electronics Packaging Technology, June 2002, p. 74-79.